Circulatory conveyor belts for conveying sheets of material to be printed are generally known in printing technology. Some of these conveyor belts are transparent. This allows detecting and identifying of sheets of print media through the belt. The conveyor belts are generally made of a strip of suitable material joined together at the ends to form an endless belt. The ends are generally laid over one another and welded or adhesively bonded together to form a seam. Since this seam can have an effect upon a printing process in a printing station, it is known to detect the seam and to control a sheet feed such that no sheets to be printed are laid over the seam and sheets are instead positioned a pre-determined distance away from the seam.
It is known to apply a marker to a printer conveyor belt, such as an opaque marker on a transparent belt, the leading edge of which opaque marker is disposed a specific distance away from the seam in the direction of travel of the conveyor belt. The position of the seam is determined by detecting the leading edge of the marker and the sheet feed is controlled on that basis. Furthermore, it is known to determine, and if necessary to correct, a cross-track alignment of the conveyor belt, i.e. at right angles to the direction of travel within the printer, using the marker.
If different types of conveyor belts, which require the use of different control parameters, are used in a printer, it is important to known which conveyor belt is currently being used in the printer. For example, some types of electrophotographic printer can use either coated or uncoated conveyor belts, which have different fuser oil absorption properties. Fuser oil is used in a fuser during fixing of toner images and can be transferred as a contaminant onto the conveyor belt during duplex printing. When conveyor belts having low absorbency are used, it may be necessary to pass blank sheets through the printer at specific intervals of time in order to clean the conveyor belt. When a more strongly absorbent conveyor belt is used, the cycle of passing blank sheets through the printer may be omitted, or the time interval between such cleaning cycles may be extended.
In some prior printers, the type of conveyor belt was manually entered by a machine operator. The printer then looked-up and applied an associated set of control parameters. Manual input presents a risk of error, particularly if the operator is inexperienced.
It would therefore be desirable to provide a method for automatic identification of the type of printer conveyor belt/control parameters in a simple way.